Inhibition of DNA topoisomerase II by azaelliptitoxins functionalized in the variable substituent domain

A series of novel C11-substituted derivatives of azaelliptitoxin (azatoxin) have been synthesized and tested for their inhibitory activity against human DNA topoisomerase II. Incorporation of a C11 polyamine or amine resulted in an increase in the intercalation properties of the drug and a decrease of topoisomerase II activity. The structure-activity relationship (SAR) profile of the nonintercalating C11 anilino azatoxin class follows the SAR of the (anilino)acridine family. 11-(4-Cyanoanilino)azatoxin (14) was found to be the most active analog in this series, exhibiting approximately 10-fold higher activity than azatoxin 12 and etoposide.